The present invention relates to thermoformed multilayer and multifunctional packaging elements, and to a process for preparing the same.
More particularly, it relates to thermoformed packaging elements endowed with a high absorption activity toward aqueous liquid substances as well as with barrier properties toward gasses such as oxygen and carbon dioxide. These packaging elements are prepared by thermoforming a multilayer and multifunctional polymeric system.
According to another aspect, the present invention relates to a process for preparing the thermoformed packaging elements, which is free from the use of adhesives and binders dispersed in solvents.
The term "thermoformed packaging element", as used in the present description and in the claims, is intended to mean whatever element, structural or not, rigid or flexible, circular or polygonal, employed in the packaging field and, particularly, containers, covers, "food-grade" panels such as, for instance, trays or boxed for the packaging of meat, vegetables, fruit or cheese.
At present, the above mentioned articles are usually obtained by the technique of thermoforming thermoplastic sheets which may be coextruded or blown, and have nearly no capacity for absorbing aqueous liquid substances.
According to another previously known technique, an absorbing layer is introduced during the packaging. Such absorbing layer is usually made of cellulose fiber having high liquid absorbing properties, and can be optionally associated with a thin and impermeable drainage layer which is made of a perforated plastic material.
However, the above packaging system has several disadvantages, one of which is its limited ability to be recycled.